Slat retract gate

ABSTRACT

A gate mechanism utilized in conjunction with various cams, followers and linkages to prevent inadvertent retraction of aircraft wing slats during flap retraction. A downward movement of the control lever is required before rotationally retracting the lever to the end of the quadrant for retracting both slats and flaps. Gate closure prevents the lever returning the same way to the slat extension position.

[ 51 June 5,1973

United States Patent [191 Fernandez 541 SLATRETRACTGATE 2,901,919 8/1959 Cravero...................... ....74/49l Inventor: gaalfos P. Fernandez, Westmimster, Primary Examiner-charles J Myhre a Assistant Examiner--F.D. Shoemaker [73] Assignee: McDonnell Douglas Corporation, Attorney-Walter J. Jason, Donald L Royer and Robert 0. Richardson et al.

Santa Monica, Calif.

July 6, 1971 [57] ABSTRACT A gate mechanism utilized in conjunction with various 22 Filed:

[21] Appl. No.: 159,722

cams, followers and linkages to prevent inadvertent retraction of aircraft wing slats during flap retraction. A downward movement of the control lever is required before rotationally retracting the lever to the [52] U.S. Cl.................r.....74/491, 74/471, 74/483 R [51] Int. Cl. ...G05g 5/02 [58] Field of Search...............,........74/526, 565, 491

end of the quadrant for retracting both slats and flaps. Gate closure prevents the lever returning the same way to the slat extension position.

[56] References Cited 4 Claims, 7 Drawing Figures UNITED STATES PATENTS 3,651,709 Booty ct al........r.r...............74/483 R PATENIEDJUH 5 I975 SHEET 2 OF 2 INVENTOR. flezajifizmwazz SLAT RETRACT GATE BACKGROUND OF PRESENT INVENTION Aircraft wings have slats along their leading edges and flaps along their trailing edges. These are used to alter the wing aerodynamics for takeoff, climb, cruise, descent and landing. On the pilots control pedestal the flaps and slats are controlled by the same lever. After takeoff, the flaps are retracted, leaving the slats partially extended until the aircraft reaches a higher speed. Because premature retraction of the slats may be dangerous, it is important to indicate to the pilot when the slats are actuated. To prevent the accidental retraction of the slats, the flap/slat control lever should be moved in a different direction after retracting the flaps.

SUMMARY OF PRESENT INVENTION The flat retract gate of the present invention prevents accidental retraction of slats as the flaps are being retracted. When the pilot moves the flap/slat lever forward to retract the flaps, the lever will engage the slat retract gate which prevents the lever from reaching the slat retracted position. Thereafter, if the pilot wants to retract the slats, the lever has to be pushed down and then moved forward. This opens the gate and allows the lever to reach the slat retracted position. After this position is reached, the gate closes and prevents the lever from returning the same way to the slat extended position. If the pilot wishes to extend the slats, the control lever has to be lifted and then moved aft. As the lever reaches the gate from the forward end, the gate will move down and allow the lever to move aft. The gate is kept is position by a spring located at its rotation axis.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the flap actuation structure;

FIG. 2 is a front end view showing slat and flap lever handles;

FIG. 3 is a side view showing the slat retraction structure; and

FIGS. 4, 5, 6 and 7 are schematic illustrations showing the various operational positions of the gate structure.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to FIG. 1 there is shown a frame 10 on which a quadrant assembly 12 is bolted by bolts 14 and 16. This quadrant serves as a guide for the pivotal movement of a flap lever 18 as it moves from one extreme position to the other. It also supports plugable detent members, not a part of this invention, to limit the degree of movement of the flap lever 18. A handle support assembly 20 is pivotally mounted at 22 to frame 10. A flap movement pushrod 24 is pivotally mounted at 26 to the handle support assembly 20 at a point spaced from pivot point 22 so that rotation of the handle support assembly 20 will cause movement of the pushrod 24. Movement of flap lever 18 in the direction of arrow 28 will first retract the flaps and continued movement then causes the slats to retract. A cam surface 30 is bolted at 32 and 34 to the handle support assembly 20 to move with it but since its function and structure is not part of the present invention, further description is not deemed pertinent.

The lower end of flap lever 18 is connected tothe handle support assembly 20 by means of parallel links 36, 38 so that flap lever 18 may be moved vertically up or down as shown by the double arrow 40 without affecting rotation of the handle support assembly 20. The lower end of lever 18 has a curve 42 against which a roller 44 on the end of a leaf spring 46 is urged to thus keep the lever in a neutral vertical position.

An L-shaped spring loaded gate lever 48 is pivotally mounted at 50 to the quadrant 12. Its front end 52 extends above the quadrants top surface when unactuated. This end has a lower recessed portion 54 which permits passage of an outwardly extending pin 56 on the flap lever 18 when so vertically aligned.

Referring now to FIGS. 2 and 3 there is a slat lever 58 that operates in a similar manner to that of the flap lever 18. This slat lever is connected by parallel links 60 and 62 to a cam support assembly 64. This assembly pivots about axis 22. A slat cam track 66 is mounted to the cam support assembly 64 for rotation about the pivot point 22. Not shown, and not part of the present invention is an arrangement whereby slat lever 58 rotates upon the manual operation of the flap lever 18. As a safety feature should the slats malfunction or jam, there is a provision for disabling or disconnecting the slat lever 58 from rotation when the flap lever 18 is rotated. This requires a vertical movement of the slat lever 58 in the direction of the arrow 68. A detent 70 is provided in the guide 72 to permit this movement. Slat lever 58 is maintained in its downward position by means of a cam surface 74 against which a roller 76 is releasably urged by leaf spring 78. actuation Pivotally mounted at 80 on frame 82 is a link assembly 84 to which is mounted a slat actuation output 86 pivotally mounted at 88. A cam follower 90 on the link assembly 84 rides within the slat cam track 66 when the track is rotated. This causes movement of the slat actuation output 86 to move along the axis of the double headed arrow 92. The slat cam track 66 is of such curvature that when the slat lever 58 is in its forward-most position against stop member 94, the cam follower 90 is at its closest or shortest distance from bearing pivot point 22 and the slat actuation output 86 is moved to its most left hand position shown in FIG. 3. The curvature of the track is such that as the slat cam track 66 pivots about pivot 22 in a counter-clockwise direction, the slat actuationg member 86 moves to the right and the slats are then in extended position. At this point, the slat lever 58 has been rotated counter-clockwise to abut against stop member 96.

Having described an illustrative embodiment incorporating the present invention, reference is now made to FIGS. 4, 5, 6 and 7 wherein is shown the various operational positions of the gate structure. In FIG. 4 the gate 48 is in its normal position with front end 52 extending above the quadrant assembly 12. Flap lever 18 is in its forward position with the pin 56 positioned slightly below the stop portion 98. This vertical position is determined by the recess 42 in lever 18 in FIG. 1 in engagement with the roller 44. The gate 48 is normally urged into the position as shown by means of a spring, not shown.

In the extension of the flap and slats the flap lever 18 is moved vertically upwardly, as shown by arrow 100, until the pin 56 is in position shown by 56A. Thereafter lever 18 is moved in the direction shown by arrow 102, and pin 56 moves against end 52 as shown in position 56B. The incline 104 on front end 52, when pushed by the pin 56, at position 568, causes it to depress. This causes the gate 48 to rotate around pivot point 50 in a clockwise direction as shown in FIG. 5. The lever then may proceed rearwardly as shown by arrow 106 in FIG. 5. This sequential movement is represented by. the pin 56 in position 56C, 56D, 56E, and 56F. This operation extends both the slats and the flaps.

In the retraction of the flaps and slats, the operation is as shown in FIGS. 6 and 7. Flap lever 18 is moved forwardly in the direction of arrow 108 from pin position 566. When the pin strikes gate end 52, it does not depress and gate end 52 stops the forward movement of the pin. This is shown in the pin position 56H. At this point the flaps have been retracted but the slats have not. This, of course, is because of the slat cam track 66 configuration shown in FIG. 3. Now, when the pilot wishes to initiate further action to retract the slats, he simply depresses on the flap lever 18 and the pin in position 56H now moves downwardly to positions 561 and SM. This permits the pin to move through the recessed portion 54 in the direction of arrow 110. The pin then moves along the ramp 112 of the gate 48, depressing it as shown in FIG. 7. This permits pin movement as shown from positions 56], 56K, 56L to position 56M. Again, because the gate 48 is spring urged, it will then move upwardly into position for the stop 98 in conjunction with a stop 114 on frame 12 to prevent the reverse movement of the pin. The gate and lever are again in the position shown in FIG. 4 and the operation is complete.

Having thus described an illustrative embodidment and the operation of the present invention, it is to be understood that other embodiments are obvious to one skilled in the art. Such variations are to be considered as within the scope of the present invention as defined by appended claims.

I claim:

I. A slat retract gate for a lever rotatably mounted to extend and retract slats and flaps on an aircraft wing,

said 'lever also being capable of radial movement relative to its pivotal axis,

said lever having a neutral radial position,

said lever having a transversely directed pin,

said lever being movable outwardly radially and thence pivotally rotatable in a first direction to move said slats and flaps to extended positions,

said gate having an end extending above said pin and being pivotally mounted and spring biased to permit one way rotation of said lever pin past said gate end in pivotal rotation of said lever in said first direction to said slats and flaps extended position,

said lever in retractingsaid flaps being pivotally rotated in the reverse direction to a flap retracted position, wherein said lever pin abuts said gate which prevents further lever rotation,

said gate having recessed means therein below said end to permit rotation in the reverse direction of said lever when radially depressed for passage of said pin past said recessed means,

said lever in retracting said slats being radially movable inwardly to said neutral position to align said pin with said recessed means and thence pivotally rotatable in said reverse direction to a slats retracted position, wherein said lever remains in said neutral radial position.

2. A slat retract gate as in claim 1 wherein said lever is connected for radial movement on a pivotally mounted support assembly, and

flap movement output means mounted on said supsaid flaps have been retracted. 

1. A slat retract gate for a lever rotatably mounted to extend and retract slats and flaps on an aircraft wing, said lever also being capable of radial movement relative to its pivotal axis, said lever having a neutral radial position, said lever having a transversely directed pin, said lever being movable outwardly radially and thence pivotally rotatable in a first direction to move said slats and flaps to extended positions, said gate having an end extending above said pin and being pivotally mounted and spring biased to permit one way rotation of said lever pin past said gate end in pivotal rotation of said lever in said first direction to said slats and flaps extended position, said lever in retracting said flaps being pivotally rotated in the reverse direction to a flap retracted position, wherein said lever pin abuts said gate which prevents further lever rotation, said gate having recessed means therein below said end to permit rotation in the reverse direction of said lever when radially depressed for passage of said pin past said recessed means, said lever in retracting said slats being radially movable inwardly to said neutral position to align said pin with said recessed means and thence pivotally rotatable in said reverse direction to a slats retracted position, wherein said lever remains in said neutral radial position.
 2. A slat retract gate as in claim 1 wherein said lever is connected for radial movement on a pivotally mounted support assembly, and flap movement output means mounted on said support assembly for actuation thereby.
 3. A slat retract gate as in claim 1 wherein a slat cam support assembly is connected for rotation with said flap lever, and cam follower means pivotally mounted for converting rotation of said slat cam support assembly into a slat actuation output.
 4. A slat retract gate as in claim 3 wherein said slat cam support assembly has a slat cam thereon of such configuration that said slats are retracted only after said flaps have been retracted. 